Hello,
there is a bug in the multiselect editor of the datatable.
You can see it here:
https://docs.webix.com/samples/60_pro/01_datatable/04_editors/08_editor_multiselect.html
On changing of the item, you will find in the console:
webix_debug.js:34184 Uncaught TypeError: Cannot read property ‘toString’ of null
Thanks,
Martin